The present invention relates to an electrophotographic recording apparatus capable of performing color printing, and, more particularly, to an electrophotographic recording apparatus having a plurality of developing devices so disposed adjacent to a photosensitive member as to be selectively moved to a position at which development can be performed at the time of the photographic recording operation.
Hitherto, electrophotographic recording apparatuses of a type having a developing unit which includes a plurality of developing devices have been disclosed in Japanese Patent Unexamined Publication Nos. 2-61665 and 2-27375 each having a developing unit incorporating a plurality of developing devices disposed in a vertical direction so that a desired developing device is moved at the time of use to a position at which development can be performed by vertically moving the developing unit. Another type has been disclosed in Japanese Patent Unexamined Publication No. 2-64569 which has a developing unit having a plurality of developing devices disposed in the vertical direction so that the developing unit is vertically moved at the time of use so as to select a desired developing device, the selected developing device being further pushed forward in the horizontal direction to the position at which development can be performed (hereinafter called a "vertical reciprocative type"). Another type has been disclosed in Japanese Patent Unexamined Publication No. 2-83557 which includes a developing unit having a plurality of developing devices disposed in the horizontal direction so that a desired developing device is moved to the position at which development can be performed by moving the aforesaid developing unit (hereinafter called a "horizontal reciprocative type"). Other types have been further disclosed in Japanese Patent Unexamined Publication Nos. 2-83557, 2-100065, 62-102261 and 60-257459, and the like each having a developing unit including a plurality of developing devices disposed in the circumferential direction thereof so that a desired developing device is moved to a position at which development can be performed by rotating the developing unit around the central axis thereof at the time of use (hereinafter called a "rotative type"). Furthermore, other types have been disclosed in Japanese Patent Unexamined Publication Nos. 3-21962 and 2-167575 each having a developing unit which includes a plurality of developing devices disposed in a sector configuration so that the developing unit is rotated to form a circular arc at the time of use, causing a desired developing device to be moved to the position at which development can be performed (hereinafter called an "arc reciprocative type").
Although the aforesaid conventional electrophotographic recording apparatuses each having a developing unit, which includes a plurality of the developing devices, are able to considerably shorten the length required to dispose the developing unit adjacent to the photosensitive member, the realized effect of shortening the length has been unsatisfactory. In particular, the aforesaid vertical reciprocative type apparatus encounters a problem in that an excessively large portion is required to dispose the developing unit in a vertical region adjacent to the photosensitive member including a passage through which the developing unit is moved. The horizontal reciprocative type apparatus similarly raises a problem in that an excessively large portion is required to dispose the developing unit in a horizontal region adjacent to the photosensitive member including a passage through which the developing unit is moved. The rotative type apparatus also raises a problem in that an excessively large portion is required to dispose the developing unit in a region adjacent to the photosensitive member including its rotation drive mechanism. Furthermore, the arc reciprocative type apparatus raises a problem in that an excessively large portion is required to dispose the developing unit in a region adjacent to the photosensitive member including its rotation drive mechanism.